c# - Can System.Net.Mail.Mailmessage be inherited? -

i tried inherit mailmessage class, can't. want introduce own properties in it.

when type public override , don't override options

here code

using system; using system.collections.generic; using system.linq; using system.web; using system.net.mail;  namespace foodmenu {     public class custommailmessage:mailmessage     {      } } 

no doubt class can inherited there no sealed keyword in declaration.

public class mailmessage : idisposable 

may there no property can overrided.